title: Characterization of a panel of monoclonal antibodies toward mouse PAI-1 that exert a significant profibrinolytic effect in vivo.
abstract: BACKGROUND
  PAI-1 is the main physiological inhibitor of t-PA and u-PA. Elevated PAI-1 levels have been implicated in the pathogenesis of several thrombotic and non-thrombotic diseases. The effect of PAI-1 inhibition can be studied in mouse models, when appropriate immunological tools are available. The majority of the available monoclonal antibodies against PAI-1 have been raised against human PAI-1. Even though some of these antibodies cross-react with non-glycosylated PAI-1 from different species, these antibodies often do not cross-react sufficiently with glycosylated mouse PAI-1. Moreover, the antibodies that cross-react with glycosylated mouse PAI-1 often have decreased inhibitory properties in the presence of vitronectin. Our objective was the generation of a panel of monoclonal antibodies reacting with vitronectin-bound glycosylated mouse PAI-1.
  
  
  RESULTS
  Five monoclonal antibodies revealed binding to glycosylated mouse PAI-1 and exerted a strong (i.e., 58-80% inhibition of PAI-1 activity) inhibitory effect toward mouse PAI-1. Similar inhibitory effects were seen in the presence of a 33-fold molar excess of vitronectin. The PAI-1 inhibitory potential of the antibodies in vivo was demonstrated in a thromboembolism model, in which the evaluated antibodies significantly increased the percentage of mice with normal physical activity in comparison to mice treated with negative control antibody.
  
  
  CONCLUSIONS
  To the best of our knowledge this is the first panel of monoclonal antibodies that can inhibit mouse PAI-1 in the presence of vitronectin and that show a profibrinolytic effect in vivo. Therefore these antibodies provide excellent immunological tools to further investigate the role of PAI-1 in mouse models.
authors.affiliation: Laboratory for Pharmaceutical Biology, Faculty of Pharmaceutical Sciences, Katholieke Universiteit Leuven, Belgium.
authors.forename: Britt
authors.initials: B
authors.lastname: Van De Craen
authors.forename: Ilse
authors.initials: I
authors.lastname: Scroyen
authors.forename: Rana
authors.initials: R
authors.lastname: Abdelnabi
authors.forename: Els
authors.initials: E
authors.lastname: Brouwers
authors.forename: H Roger
authors.initials: HR
authors.lastname: Lijnen
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Declerck
authors.forename: Ann
authors.initials: A
authors.lastname: Gils
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D003429:Cross Reactions; D004195:Disease Models, Animal; D018604:Epitope Mapping; D006031:Glycosylation; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D023421:Models, Animal; D017395:Plasminogen Activator Inhibitor 1 / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D013923:Thromboembolism / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism; D019096:Vitronectin / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D017395:Plasminogen Activator Inhibitor 1; D019096:Vitronectin